Crank case ventilator



0, 1931- A. J. SYROVY ET AL I 1,828,035

CRANK CASE VENTILATOR Filed April 9, 1928 Patented Oct. 20, 1931 UNITEDSTATES PATENT OFFItZE AUGUSTINE J'. SYROVY AN 1) ROBERT N. JANEWAY, FDETROIT, MICHIGAN, ASSIGNORS,

IBY MESNE ASSIGNMENTS, TO CHRYSLER CORPORATION, A CORPORATION OF DELA-WARE CRANK CASE VENTILATOR.

Application filed April 9,

l bustion engine whereby the crank case may be kept entirely free fromwater vapor and vaporized gasoline.

An object of this invention is to provide a crank case ventilator whichmay be oper- 1. ated by the exhaust gases from the engine.

A further object of this invention is to provide a crank case ventilatorwhich will be exceedingly simple in construction and yet thoroughlyeflicient in operation.

Other objects and advantages of this invention will become apparent asthe following description proceeds, particularly when reference is hadto the accompanying drawings wherein:

Figure 1 is an elevational view of a vehicle engine showing theinvention applied to the same; and

Figure 2 is an enlarged detail sectional view of the device shownapplied to the engine in Figure 1.

Referring now particularly to the drawings wherein like referencecharacters designate corresponding parts, indicates generally aninternal combustion engine having a crank case 11 and the exhaustmanifold 12. The exhaust manifold is bent downwardly at its rear end andis provided with the flange 13 for attachment in any suitable manner tothe flanged end 14 of a substantially verti cally extending conduit 15which forms the continuation of the exhaust manifold for conducting theexhaust gases to the muffler (not shown). As clearly shown in Figure 1the crank case is provided with the valve cover plates 16 according tothe usual practice.

The invention contemplates the utilizationof the flow of exhaust gasesthrough the exhaust manifold to create a suction in an ejector conduitand further contemplates the transmission of this suction to the crankcase to remove the undesirable gases from the crank case. Accordinglythere is provided a tube or conduit 17 which opens laterally into thecrank case 11 through one of the cover plates 16 as through a packedfitting 18.

1928-. Serial No. 268,754.

The tube or conduit 17 extends rearwardly toward the vertical portion 15of the exhaust manifold where it is connected in any suitable manner to.a short section of tubing 19 mounted in the wall of the exhaustmanifold. The connection between the conduit 17 and tubing 19 may beeffected by a gland 20 and nipple 21 as clearly illustrated in Figure 2of the drawings. the exhaust manifold so that its outlet end 22 liessubstantially centrally of the vertical portion 15 of the exhaustmanifold and opens in the direction of flow of the exhaust gases throughthe said exhaust manifold.

To increase the velocity of the flow of the exhaust gases past theoutlet 22 of the tube 19 there is provided a member forming a Venturipassage around the free end of the tube 19. This member preferablycomprises a sheet steel tube 23 shaped to form a Venturi passage andprovided at one end with the.

flange 24: adapted to be received between the flanges 13 and 14- whichjoin the two sections of the exhaustmanifold to each other. The tube 23is so positioned with respect to the tube 19 that its portion 25 whichforms the throat of the Venturi passage surrounds the outlet 22 of thetube 19.

It has been found that the Venturi passage, although fairly eflicienthas definite limitations as an ejector when applied to the engine.

exhaust. As the throat diameter is decreased not only does the pressureat the throat tend to diminish but also the pressure ahead of theventuri tends to increase. It has been found in. this case that when thediameter of the throat of the Venturi passage is about of the inletdiameter of the pressure the pres sure at the throat reaches a minimumand the invention therefore contemplates the shaping of the tube 23 insuch a manner that the throat of the Venturi passage will assumesubstantially this proportion to the inlet diameter of the Venturipassage.

It has also been found that a considerable velocity gradient existsacross the passage diameter, the velocity being greatest at the centerand least at the walls. Accordingly therefore, the inventioncontemplates the arrangement of the outlet end 22 of the tube 19 Thetube 19 is bent within.

at the center of the throat of the Venturi passage so that the outletend of the tube is thus exposed to the maximum velocity of the exhaustgases.

From the above, it is believed that the operation of the device will beclearly apparent. The exhaust gases flowing through the exhaust manifoldwill have their velocity increased by the Venturi passage and will thuscreate a considerable suction in the tube 19. This suction will betransmitted through the tube 17 to the crank case 11 to draw fresh airthrough the said crank case thereby removing ases and water vapor whichmight tend to lute the oil within the crank case and rust the adjacentmotor parts.

It will thus be apparent that the invention provides simple and positivemeans for withdrawing the undesirable gases from the crank case and thatthe structure may be applied to practically any internal combustionengine of standard construction. While one embodiment of the inventionhas been described considerably in detail, it is to be clearlyunderstood that the description is for the purpose of illustration onlyand that the right is therefore reserved to make such changes in thedetails of construction and arrangement of parts as will fall within thepurview of the attached claims.

WV hat we claim as 1. In a crank case our invention is: ventilator, acrank case, an exhaust manifold, a conduit for withdrawing gases fromthe said crank case and discharging the same into the said exhaustmanifold, the said conduit having its inlet end communicating with thesaid crank case and its outlet end within the said exhaust manifold andopening in the direction of flow of the exhaust gases through the saidmanifold, and means for increasing the velocity of the flow of theexhaust gases within the said manifold as they pass the outlet end ofthe said conduit to increase the suction within the said conduit, saidmeans including a sheet metal tubular member clamped within said exhaustmanifold and forming a Venturi passage therein adjacent the outlet endof the said conduit.

2. In a crank case ventilator, a sectional crank case, an exhaustmanifold, a member within the said exhaust manifold forming a Venuripassage, said member having a flange clamped between thesections of themanifold and a conduit having its inlet end communicating with the saidcrank case and its outlet end within the said exhaust manifold andarranged centrally of the throat of the Venturi passage formed therein,the outlet opening of the said conduit being arranged to face in thedirection of flow of the exhaust gases through the said exhaustmanifold.

3. In a crank case ventilator, a crank case, an exhaust manifold, amember within the said exhaust manifold forming a Venturi pastures.

AUGUSTINE J. SYROVY. ROBERT N. JANEWAY.

